/*
 * Licensed to the Apache Software Foundation (ASF) under one or more contributor license agreements. See the NOTICE
 * file distributed with this work for additional information regarding copyright ownership. The ASF licenses this file
 * to You under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the
 * License. You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on
 * an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the
 * specific language governing permissions and limitations under the License.
 */
package org.apache.tuweni.bytes;

import static com.google.common.base.Preconditions.checkArgument;
import static com.google.common.base.Preconditions.checkElementIndex;

import java.nio.ByteBuffer;
import java.util.Arrays;

class ByteBufferWrappingBytes extends AbstractBytes {

    protected final ByteBuffer byteBuffer;
    protected final int offset;
    protected final int length;

    ByteBufferWrappingBytes(ByteBuffer byteBuffer) {
        this(byteBuffer, 0, byteBuffer.limit());
    }

    ByteBufferWrappingBytes(ByteBuffer byteBuffer, int offset, int length) {
        checkArgument(length >= 0, "Invalid negative length");
        int bufferLength = byteBuffer.capacity();
        if (bufferLength > 0) {
            checkElementIndex(offset, bufferLength);
        }
        checkArgument(
                offset + length <= bufferLength,
                "Provided length %s is too big: the value has only %s bytes from offset %s",
                length,
                bufferLength - offset,
                offset);

        this.byteBuffer = byteBuffer;
        this.offset = offset;
        this.length = length;
    }

    @Override
    public int size() {
        return length;
    }

    @Override
    public int getInt(int i) {
        return byteBuffer.getInt(offset + i);
    }

    @Override
    public long getLong(int i) {
        return byteBuffer.getLong(offset + i);
    }

    @Override
    public byte get(int i) {
        return byteBuffer.get(offset + i);
    }

    @Override
    public Bytes slice(int i, int length) {
        if (i == 0 && length == this.length) {
            return this;
        }
        if (length == 0) {
            return Bytes.EMPTY;
        }

        checkElementIndex(i, this.length);
        checkArgument(
                i + length <= this.length,
                "Provided length %s is too big: the value has size %s and has only %s bytes from %s",
                length,
                this.length,
                this.length - i,
                i);

        if (length == 32) {
            return new ByteBufferWrappingBytes32(byteBuffer, offset + i, length);
        }

        return new ByteBufferWrappingBytes(byteBuffer, offset + i, length);
    }

    // MUST be overridden by mutable implementations
    @Override
    public Bytes copy() {
        if (offset == 0 && length == byteBuffer.limit()) {
            return this;
        }
        return new ArrayWrappingBytes(toArray());
    }

    @Override
    public MutableBytes mutableCopy() {
        return new MutableArrayWrappingBytes(toArray());
    }

    @Override
    public void appendTo(ByteBuffer byteBuffer) {
        byteBuffer.put(this.byteBuffer);
    }

    @Override
    public byte[] toArray() {
        if (!byteBuffer.hasArray()) {
            return super.toArray();
        }
        int arrayOffset = byteBuffer.arrayOffset();
        return Arrays.copyOfRange(
                byteBuffer.array(), arrayOffset + offset, arrayOffset + offset + length);
    }

    @Override
    public byte[] toArrayUnsafe() {
        if (!byteBuffer.hasArray()) {
            return toArray();
        }
        byte[] array = byteBuffer.array();
        if (array.length != length || byteBuffer.arrayOffset() != 0) {
            return toArray();
        }
        return array;
    }
}
